• 한국발생생물학회지:발생과생식
• /
• 제17권1호
• /
• pp.1-8
• /
• 2013

Osteoprotegerin (OPG) is a secreted glycoprotein that regulates bone resorption by inhibiting differentiation and activation of osteoclast, thereby potentially useful for the treatment of many bone diseases associated with increased bone loss. In this study, we designed a novel cDNA expression cassette by modifying the potent and mammary gland-specific goat ${\beta}$-casein/hGH hybrid gene construct and examined human OPG (hOPG) cDNA expression in transgenic mice. Six transgenic mice all successfully expressed hOPG in their milk at the level of 0.06-2,000 ${\mu}g/ml$. An estimated molecular weight of the milk hOPG was 55 kDa in SDS-PAGE, which is the same as a naturally glycosylated monomer. This hOPG expression was highly specific to the mammary glands of transgenic mice. hOPG mRNA was not detected in any organs analyzed except mammary gland. Functional integrity of milk hOPG was evaluated by TRAP (tartrate-resistant acid phosphatase) activity assay in bone marrow cell cultures. OPG ligand (OPG-L) treatment increased TRAP activity by two fold but it was completely abolished by co-treatment with transgenic milk containing hOPG. Taken together, our novel cDNA expression cassette could direct an efficient expression of biologically active hOPG, a potential candidate pharmaceutical for bone diseases, only in the mammary gland of transgenic mice.

• Biomolecules & Therapeutics
• /
• 제21권3호
• /
• pp.204-209
• /
• 2013

Osteoprotegerin (OPG) is a secreted glycoprotein and a member of the tumor necrosis factor receptor superfamily. It usually functions in bone remodeling, by inhibiting osteoclastogenesis through interaction with a receptor activator of the nuclear factor ${\kappa}B$ (RANKL). Transglutaminases-2 (Tgase-2) is a group of multifunctional enzymes that plays a role in cancer cell metastasis and bone formation. However, relationship between OPG and Tgase-2 is not studied. Therefore, we investigated the involvement of 12-O-Tetradecanoylphorbol 13-acetate in the expression of OPG in MG-63 osteosarcoma cells. Interleukin-$1{\beta}$ time-dependently induced OPG and Tgase-2 expression in cell lysates and media of the MG-63 cells by a Western blot. Additional 110 kda band was found in the media of MG-63 cells. 12-O-Tetradecanoylphorbol 13-acetate also induced OPG and Tgase-2 expression. However, an 110 kda band was not found in TPA-treated media of MG-63 cells. Cystamine, a Tgase-2 inhibitor, dose-dependently suppressed the expression of OPG in MG-63 cells. Gene silencing of Tgase-2 also significantly suppressed the expression of OPG in MG-63 cells. Next, we examined whether a band of 110 kda of OPG contains an isopeptide bond, an indication of Tgase-2 action, by monoclonal antibody specific for the isopeptide bond. However, we could not find the isopeptide bond at 110 kda but 77 kda, which is believed to be the band position of Tgase-2. This suggested that 110 kda is not the direct product of Tgase-2's action. All together, OPG and Tgase-2 is induced by IL-$1{\beta}$ or TPA in MG-63 cells and Tgase-2 is involved in OPG expression in MG-63 cells.

• Journal of Korean Medical Science
• /
• 제33권53호
• /
• pp.322.1-322.14
• /
• 2018

Background: Osteoprotegerin (OPG) plays protective roles against the development of vascular calcification (VC) which greatly contributes to the increased cardiovascular events in patients with chronic kidney disease (CKD). The present study aimed to find the non-traditional, kidney-related cardiovascular risk factors correlated to serum OPG and the effect of serum OPG on the arterial stiffness measured by brachial ankle pulse wave velocity (baPWV) in patients with the pre-dialysis CKD. Methods: We cross-sectionally analyzed the data from the patients in whom baPWV and the serum OPG were measured at the time of enrollment in a prospective pre-dialysis CKD cohort study in Korea. Results: Along with traditional cardiovascular risk factors such as age, diabetes mellitus, pulse pressure, and baPWV, non-traditional, kidney-related factors such as albuminuria, plasma level of hemoglobin, total $CO_2$ content, alkaline phosphatase, and corrected calcium were independent variables for serum OPG in multivariate linear regression. Reciprocally, the serum OPG was positively associated with baPWV in multivariate linear regression. The baPWV in the 3rd and 4th quartile groups of serum OPG were higher than that in the 1st quartile group after adjustments by age, sex and other significant factors for baPWV in linear mixed model. Conclusion: Non-traditional, kidney-related cardiovascular risk factors in addition to traditional cardiovascular risk factors were related to serum level of OPG in CKD. Serum OPG level was significantly related to baPWV. Our study suggests that kidney-related factors involved in CKD-specific pathways for VC play a role in the increased secretion of OPG into circulation in patients with CKD.

• 대한지역사회영양학회지
• /
• 제16권6호
• /
• pp.762-770
• /
• 2011

Osteoprotegerin (OPG) plays a core role in bone reformation by antagonizing the effect of receptor activator of nuclear factor ${\kappa}$-B ligand (RANKL), and mediates vascular calcification in cardiovascular disease patients. Thus, we aimed to examine the relationship between serum OPG levels and cardiovascular factors and inflammatory markers in metabolic syndrome patients (MS). This cross-sectional study included 96 men who visited the diet clinic between May and July 2011. Patients were classified into 2 groups based on NCEP-ATP guidelines: normal and with MS (n = 50 and 46, respectively). Physical measurements, biochemical assay were measured. Serum OPG and IL-6, diponectin and hs-CRP were assessed. MS were aged $50.02{\pm}10.85$ years, and normal patients $52.07{\pm}9.56$ years, with no significant differences. Significant differences were not observed in BMI between the 2 groups. Moreover, significant differences were not observed in serum OPG, however, the serum OPG level ($4.41{\pm}1.86pmol/L$) differed significantly between an overweight MS (BMI > 25) and normal patients. OPG was correlated to age (r = 0.410, p = 0.000), HDL-cholesterol (r = 0.209, p = 0.015), and log adiponectin (r = 0.175, p = 0.042). Multiple regression analyses using the enter method showed that age (${\beta}$ = 0.412, p = 0.000) and BMI (${\beta}$ = 0.265, p = 0.000) considerably affected OPG. In conclusion, out study showed that serum OPG levels are correlated with cardiovascular risk factors, such as BMI, HDL-cholesterol and adiponectin in MS and adiponectin, suggesting that serum OPG has potential as a cardiovascular disease indicator and predictor.

• 대한치과교정학회지
• /
• 제38권3호
• /
• pp.159-174
• /
• 2008

치아이동 시 피질골 천공이 치조골 재형성에 미치는 영향을 알아보기 위해서 생후 15주된 자성백서를 사용하여 피질골 천공 후 치아이동을 실시한 실험군(Tooth movement with cortical punching: TMC group, n = 16)과 교정적 치아이동만 실시한 대조군(Tooth movement only group: TM group, n = 16)의 치아주위조직을 면역조직화학염색을 통하여 관찰하였다. 실험군과 대조군의 실험동물에 20 gm의 힘으로 상악 전치부 사이를 이개시키는 치아이동을 시행하였으며 실험군에서는 상악 전치부 구개부위에 피질골 천공을 실시하였다. 치아이동 후 1, 4, 7, 14일째에 실험군과 대조군의 실험동물을 희생시켰다. 면역조직화학염색법으로 OPG, RANK, RANKI의 발현을 비교한 결과, OPG의 발현은 양 군 모두에서 미처치 대조군에 비하여 감소되었으나, 실험군에서의 발현이 대조군보다 컸으며, RANK, RANKL은 피질골 천공을 시행한 경우에 더 강한 발현을 보이는 것이 관찰되었다. 따라서 피질골 천공이 치주조직의 OPG, RANK, RANKL의 발현에 영향을 미치며 치조골의 재형성을 향상시키는 것을 알 수 있었다.

• 대한소아치과학회지
• /
• 제33권2호
• /
• pp.290-303
• /
• 2006

치아의 맹출은 치아기 (dental organ)와 치조골의 세포와 연관된 매우 복잡한 과정이다. 우선 치아 맹출이 일어나기 전에 파골세포가 치낭으로 집결하게 된다. 이러한 치낭의 역할은 파골세포와 조골세포의 상호작용으로 이루어지는 골개조와 밀접한 관련이 있는데 이는 치아 맹출과 연관된 많은 유전자들이 치낭에서 발현되기 때문이다. RANKL는 TNF ligand family로써 조골세포에 존재하며 파골세포의 형성 및 전구세포로 부터의 활성화를 유도한다. 이러한 RANKL는 OPG에 의해 그 작용이 억제되며 RANKL와 OPG의 상대적인 비율이 파골세포의 형성에 영향을 미친다. 또한 Runx2 유전자의 변이는 조골세포의 분화와 활성 에 차질을 가져오고 결국 RANKL/OPG pathway를 통해 파골세포 형성에 영향을 줄 수 있다. 치아의 발육 및 맹출에 미치는 RANKL및 OPG의 영향을 알아보고 Runx2와의 연관성을 알아보기 위해 in situ hybridization방법으로 태생 1, 3, 5, 7, 9, 11일된 쥐의 하악 및 제1대구치를 사용하여 실험을 실시한 결과 RANKL, OPG, Runx2의 mRNA가 태생 1일부터 11일까지 치낭 및 치아주위조직에 특성 있게 나타났다. 이중 태생 5일에서 9일 사이에 RANKL 및 Runx2는 치아의 교합면측과 하방 치조골 부위의 발현이 강하게 나타난 반면 OPG는 약한 발현을 보였다. 이는 또한 파골세포의 활성부위를 알아보기 위해 TRAP염색을 실시하여 태생 5일에서 9일 사이에 최대의 활성화를 나타낸 결과와 연관성 있게 나타났다. RANKL, OPG, Runx2의 특성 있는 발현양상들을 종합해 볼 때, 치아 맹출은 치낭, 치아기, 치조골 사이의 상호 작용을 통해 이루어지며, 이는 치낭이 치아 맹출에 있어서 매우 중요하다는 것을 의미한다. 또한, 이러한 유전자들 (RANKL, OPG, Runx2) 이 치아의 맹출에 중요한 역할을 하는 것으로 사료된다.

• Journal of Periodontal and Implant Science
• /
• 제43권5호
• /
• pp.227-232
• /
• 2013

Purpose: The receptor activator of nuclear factor kappa B (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system plays a significant role in osteoclastogenesis, activation of osteoclasts, and regulation of bone resorption. This study aimed to evaluate the use of the salivary soluble RANKL (sRANKL)/OPG ratio as a diagnostic marker for periodontitis in nonsmokers. Methods: Twenty-five patients with chronic periodontitis and 25 individuals with a healthy periodontium were enrolled in this study. Samples containing 5 mL of unstimulated saliva were obtained from each subject. Salivary sRANKL and OPG concentrations were determined using a standard enzyme-linked immunosorbent assay. Statistical analysis was performed using SPSS ver. 18.0. Results: The levels of sRANKL and OPG were detectable in all of the samples. Positive relationships were found between the plaque index and clinical attachment level and both the salivary concentration of sRANKL and the salivary sRANKL/OPG ratio (P<0.05). The salivary concentration of sRANKL and the sRANKL/OPG ratio were significantly higher in the periodontitis group than in the healthy group (P=0.004 and P=0.001, respectively). In contrast, the OPG concentration showed no significant differences between the groups (P=0.455). Conclusions: These findings suggest that the salivary sRANKL/OPG ratio may be helpful in the screening and diagnosis of periodontitis. However, longitudinal studies with larger populations are needed to confirm these results.

• Journal of Periodontal and Implant Science
• /
• 제38권sup2호
• /
• pp.395-404
• /
• 2008

Purpose: Osteoprotegerin (OPG) is a secreted glycoprotein and a member of the tumor necrosis factor (TNF) receptor family that inhibits bone resorption by suppressing osteoclastogenesis. Gingival fibroblasts (GF) play a role in periodontal disease progression, and the purpose of this experiment was to evaluate influence of osteotropic factors on the expression of osteoprotegerin mRNA in these cells. Materials and Methods: In this experiment, the influence of osteoclastogenic factors, interleukin-1 beta (IL-$1{\beta}$), TNF-$\alpha$, prostanglandin E2 ($PEG_2$). parathyroid hormone (PTH) and 1$\alpha$, 25-dihydroxyvitamin $D_3$ on the expression of osteoprotegerin mRNA in GF was studied by Northern blot hybridization. Results: As expected, $PEG_2$ tended to inhibit OPG levels and this was most prominent at 24 hours of culture with $10^{-7}M$ of $PEG_2$. TNF-$\alpha$ at 10ng/ml and also at 25ng/ml decreased OPG levels to almost 30% of the control at 24 hours. This contrasts with reports of increased OPG levels from osteoblast/stromal cells and gingival fibroblasts stimulated by TNF-$\alpha$. Decrease of OPG levels with $PEG_2$ and TNF-$\alpha$ suggests a pathway whereby these mediators exert their resorptive effects. However, OPG levels were increased almost 3-fold at 24 hours with IL-1$\beta$(1 to 15ng/ml) and increased 1.4 fold with 24-hour treatment of $10^{-7}M$ PTH. Conclusion: Increase of OPG levels suggests that these 'osteoclastogenic' factors act in more complex ways and may act to inhibit bone resorption in inflammatory periodontitis. This result supports the role of OPG as a negative feedback mechanism in osteoclastic activity.

• 운동영양학회지
• /
• 제23권1호
• /
• pp.13-20
• /
• 2019

[Purpose] The OPG/RANK/RANKL signaling is a new family of bone metabolism biomarkers belonging to the immune system. However, the bone metabolism response to long-term exercise in the RANKL/RANK/OPG signaling is less evident. The purpose of this study was to examine these biomarkers in healthy college females after 12-weeks combined exercise intervention. [Methods] Participants (N=22, 22.4±1.3yrs) were randomly divided in two different group: 12 in the control group and 10 in the exercise group performing combined exercise program that interventions was conducted 3 times per week for 12 weeks. The outcome measures included serum concentrations of RANKL, OPG and bone metabolic cytokines such as TNF-α and IL-6, and mRNA expressions of same variables from PBMC. VO_2max and bone mineral density (BMD) were measured at before and after exercise intervention. [Results] There were no significant differences in the serum RANKL, OPG concentrations and all RANKL/RANK/OPG signaling mRNA expression on interaction effect between group and time (NS). Also no significant differences were found in the serum TNF-α and IL-6 concentrations and mRNA expression (NS). The IL-6 mRNA expression only showed significant difference in the main effect of groups (p<.05). There were also no significant differences in the VO_2max and BMD on interaction effect between group and time (NS). [Conclusion] These results suggested that there were no effects on bone mineral density and RANKL/RANK/OPG signaling without the effect of 8-weeks combined exercise on cardiovascular endurance fitness.

• Molecules and Cells
• /
• 제25권3호
• /
• pp.352-357
• /
• 2008

Osteoprotegerin (OPG) is a soluble decoy receptor that inhibits osteoclastogenesis and is closely associated with bone resorption processes. We have designed and determined the solution structures of potent OPG analogue peptides, derived from sequences of the cysteine-rich domain of OPG. The inhibitory effects of the peptides on osteoclastogenesis are dose-dependent ($10^{-6}M-10^{-4}M$), and the activity of the linear peptide at $10^{-4}M$ is ten-fold higher than that of the cyclic OPG peptide. Both linear and cyclic peptides have a ${\beta}$-turn-like conformation and the cyclic peptide has a rigid conformation, suggesting that structural flexibility is an important factor for receptor binding. Based on structural and biochemical information about RANKL and the OPG peptides, we suggest that complex formation between the peptide and RANKL is mediated by both hydrophobic and hydrogen bonding interactions. These results provide structural insights that should aid in the design of peptidyl-mimetic inhibitors for treating metabolic bone diseases caused by abnormal osteoclast recruitment.